FI84276C - Pressure sensitive silicone adhesive composition - Google Patents

Description

84276

Squeeze screen si 1 Icon adhesive composition

The present invention is directed to an additive-reactive, pressure-sensitive s11 icon composition that can be vulcanized to provide a pressure-sensitive adhesive.

The pressure-sensitive adhesive 11 has a high adhesion volume, heat resistance and cohesive strength, which are the properties required of a pressure-sensitive adhesive. In addition, they have 1 heat resistance, cold resistance and electrical properties, etc., and are therefore commonly used for electrical insulation tape, which must be very safe to use, and for numerous pressure-sensitive products, which must withstand hot and cold.

In general, organoperoxide vulcanizable compositions are used as compression-sensitive silicone compositions. The composition vulcanized by the addition reaction between an alkenyl-containing organopolysiloxane and an organopolysiloxane having a hydrogen bond to a hydrogen atom is also described in U.S. Patent Nos. 54-37907 (37907/79).

However, said organoperoxide vulcanizable compositions must be vulcanized by heating to a temperature of at least 130 ° C to convert them to Puri stus sensitive Hima. As a result, they cannot be used with poorly heat-resistant substrates.

In addition, the above-mentioned addition vulcanizable composition suffers from variations in the adhesion resistance due to the difficulties in forming a film having good physical properties of the substrate.

Research has been made to overcome the above-mentioned problems of the prior art, and the present invention has been developed as a result.

84276

It is an object of the present invention to provide a pressure-sensitive adhesive composition which can be vulcanized at relatively low temperatures to a pressure-sensitive adhesive having excellent adhesion and adhesion.

This and other objects, which will become apparent upon consideration of the following description and appended claims, are achieved by the compositions of the present invention, in short, an alkenyl group-containing silicone polymer having a rubbery composition, an organic solvent solution, a tackifying silicone resin, an alkenyl group catalyst.

The present invention relates to a pressure-sensitive silicone adhesive composition containing (A) 30 to 70 parts by weight of a polydiorganosiloxane having the general formula R'R2SiO (R2SiO) nSiR2R ', wherein R represents a monovalent hydrocarbon group, R' represents an alkenyl group and R 'represents an alkenyl group (B) 30 to 70 parts by weight of an organopolysiloxane consisting of R''3Si0} y 2 ~ units and SiO2 ~ units, the molar ratio of the former units being 0.6: 1 to 0.9: 1, where R ' 'represents a group selected from alkyl groups, alkenyl groups and hydroxyl groups, at least 95% of all R' 'groups being methyl groups, (C) a certain amount of organohydrogenpolysiloxane having on average at least 2 silicone-bonded hydrogen atoms in each molecule, said amount being sufficient to provide 1 to 20 silicon-bonded hydrogen atoms per alkenyl group of component (A), (D) a silicon-bonded catalyst of the platinum-containing catalyst for the addition reaction of phenyl groups and silicone-bonded hydrogen atoms, in an amount sufficient to guarantee 0.1 to 1,000 parts by weight of platinum for each part per million by weight of the combined amount of components (A) to (C), and (E) 25 to 400 parts by weight organic solvent by weight for 3,84276 components (A) to (C). The invention is characterized in that the average of the number n is sufficient to give the polydiorganosiloxane a viscosity of at least 500,000 cP at 25 ° C.

As described above, component (A) is the main vulcanizable component of the pressure-sensitive adhesive composition of the present invention, and its vulcanization occurs by an addition reaction with component (C) under the influence of the catalytic action of component (D).

Said component (A) must have an alkenyl group essential for the addition reaction at each end of its molecule. This means that each R 'component (A) in the above formula must have an alkenyl group such as vinyl, allyl or propenyl. The vinyl group is the preferred alkenalkyl group.

The formula R of the above component (A) may be any monovalent hydrocarbon group such as an alkyl group such as methyl, ethyl and propyl, an alkenyl group such as vinyl, allyl and propenyl or an aryl group such as phenyl. In general, methyl is the preferred R group.

When R is alkenyl, vinyl is the preferred alkenyl group. When better heat resistance is required, the phenyl group and the methyl group are both present, optionally in equal amounts.

It is important that the molecular weight of component (A), and thus the value of n, corresponds to a viscosity of at least 500,000 cP (centipoise) and preferably at least 1,000,000 cP measured at 25 ° C. For example, when all R groups are methyl or optionally about 5% vinyl And the rest is methyl, the average of n is greater than about 1500, and preferably greater than about 1800. The corresponding value of n for the other 4 84276 R groups depends on those R groups, which are involved in polydiorganosi1 oxane. In general, so-called silicone rubbers are considered the best, in which case the value of n can be as high as 5000 and more.

Polydiorganosiloxanes are known to be well known in the organosilicon technique, and their syntheses need not be described herein. Usually, the alkenyl-containing terminating reactant, such as divinyltetramethyldi-siloxane, is equilibrated with a reactive diorganosyl oxane 11a, such as octamethylcyciotetracyl oxane 11a, in the presence of an acidic or alkaline catalyst. The phenyl group-containing and / or vinyl group-containing diorganosiloxane starting material may also be included in the reaction mixture to include phenyl and / or vinyl groups in the polymer chain, if desired. In addition, phenyl groups may be attached to the alkenyl group-containing terminating agent, if desired. The molecular weight of the polydiorganosiloxane can be controlled by the use of an appropriate amount of a terminating reactant in a known manner.

Component (B) of the compositions of the present invention is an organopolysiloxane which gives 1 expression to a vulcanized, Puri stus sensitive adhesive. In the above formula for the sioxane units of component (B), R "is one or the first group selected from alkyl groups such as methyl, ethyl or propyl, alkenyl groups such as vinyl and allyl, and hydroxyl group, provided that at least 95 mol% a all R "groups are methyl. Preferably, all R "groups are methyl. In general, component (B) contains the remaining si 1 anoi 1 groups derived from the hydrolysis of reactive silanes used to prepare component (B).

In component (B), the molar ratio of R "3Si units to SiO 2 units 5,84276 is preferably in the range of 0.6: 1 to 0.9: 1. The adhesiveness of the pressure-sensitive Hima decreases when there are 3 1/2 fewer R" S10 units than 0.6 per SiO 2 unit, while the cohesive force decreases when the ratio is greater than 0.9: 1.

Methods for synthesizing such organopolysiloxanes are known. The descriptions of U.S. Patent Nos. 2,676,182 and 3,284,406 are incorporated herein by reference to describe the preparation of organopolysiloxanes suitable as component (B) in the compositions of the present invention. In the compositions of the present invention, component (C) is a component that acts as a crosslinking vulcanizing agent for component (A). The vulcanization takes place by the addition reaction of the hydrogen atoms of this component si 11 with the alkenyl groups of component (A) under the influence of the catalytic action of component (D).

Component (C) may be any currently known organo-hydrogen polyoxane having an average of at least two, and preferably three or more, silicon-containing hydrogen atoms in each molecule. The molecular structure of this component is not important and may be annular, linear, branched and / or networked if desired. The organic groups of component (C) may be any one of your valent a hydrocarbon groups having no aliphatic unsaturation, as is well known, such as the general and specific alkyl and aryl groups mentioned above in component (A). In order to obtain the greatest possible compatibility of components (A), (B) and (C), the organic groups of each component are preferably the same.

In a preferred embodiment of the present invention, component (C) is a linear methylhydrogen polyoxane consisting of methylhydrogensiloxane units and optionally dimethylisoxane units. The terminal siloxane units of this linear siloxane are not important and may be 6,84276 triorganosiloxane or diorganohydrogensiloxane units or mixtures thereof in which the organic groups are, for example, methyl.

The amount of component (C) is sufficient to guarantee 1-20 silicone-bonded hydrogen atoms per alkenyl group of component (A). Component (D) is a platinum-containing catalyst and promotes the addition reaction of component (A) with component (C). Specific examples include chloroplatinic acid, chloroplatinic acid-olefin complexes, chloroplatinic acid-vinylsiloxane complexes, and platinum supported on a microparticulate carrier such as alumina.

Component (D) is added in an amount sufficient to give 0.1 to 1000, and preferably 1 to 300 parts by weight of platinum per part per million by weight of the combined amount of components (A) to (C). The crosslinking reaction is unsatisfactory of less than 0.1 parts, and therefore the cohesive force is reduced, while more than 1000 parts is disadvantageous due to the resulting short operating time and high cost.

Component (E) acts to dissolve components (A) to (D) so that the pressure-sensitive adhesive composition of the present invention can be easily applied to various substrates. Specific examples of this component include hi 11 hydrogen solvents such as toluene, xylene and 1-benzene, as well as halogenated hi 111 hydrogen solvents, but no particular limitation is imposed on this component as long as it is an organic solvent capable of dissolving components (A) to (C) and does not inhibit the above. the addition reaction.

In addition to components (A) to (E), any addition reaction inhibitor known in the art may be added to the compositions of the present invention. Specific examples of these include enines such as 3-methyl-3-penten-1-one and 7,84276 3,5-dimethyl-3-hexen-1-one; alkynyl alcohols such as 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 3-methyl-1-pentynyl-3-ol and phenylbutynol; unsaturated esters such as alkyl and substituted alkyl maleates; and polymethylvinylcycloisoxane.

In addition, small amounts of ancillary components may be added to the compositions of the present invention. Such ancillary components include, for example, numerous antioxidants, colorants, stabilizers, fillers, and the like.

For substrates for pressure sensitive adhesive products that can be obtained using the pressure sensitive adhesive composition of the present invention, numerous materials are useful in this context, for example plastic films such as polyester, polytetrafluoroethylene and polyimide films, paper such as Japanese paper and synthetic paper, textiles, textiles, textiles.

The present invention is further illustrated, but not limited, by the following illustrative examples. In the examples, part = part by weight and Ϊ s% by weight. Viscosities have been measured at 25 ° C. The properties mentioned in the examples have been measured by the following methods.

Adhesion force measurement

The pressure-sensitive machine composition was applied to a substrate of a certain thickness, followed by vulcanization by heating. The resulting pressure-sensitive tape was compressed using a 2 kg knob on a stainless steel plate (SUS304) pre-polished with No. 280 water-resistant sandpaper. 3 m / min to measure the gripping force, expressed in g / 2.5 cm.

8 84276

Cohesive force measurement

The spray-sensitive tape produced as in the previous adhesion force measurement was pressed into a surface area corresponding to a length of 20 mm and 10 mm of a stainless steel plate (SUS304) previously polished with No. 280 waterproof sandpaper. width, using a 2 kg roll. A 500 g load was applied to the lower end of the pressure sensitive strip o and hung in a 100 ° C oven for 2 hours. The slip was measured using a microscope and expressed in mi 11i meters.

Listen! 1 measurement of likeness

The pressure-sensitive tape produced as in the measurement of the adhesion volume was placed in a ball-side upward test apparatus (Tester Sangyo Kabushiki Kaisha) inclined at an angle of 30 ° C. Steel balls of different sizes were rolled down from a 10 cm long 1 starting track. The value given is the diameter of the largest steel ball, in units of 0.07938 cm, which stopped 10 cm far on the surface. For example, the value given 10 means that a steel ball with a diameter of 0.7938 cm is the largest steel ball that stopped on the surface. This measurement was performed at room temperature.

Example 1

Exactly 55 parts of methylpolysiloxane consisting of Me SiO 3 1/2 and SiO 2 units in a molar ratio of 0.7: 1, 45 parts of dimethyl-n-nyl-1-oxy-polydimethylsiloxane rubber having a vinyl group content of 0.02%, 0, 2 parts of trimethyl-1-oxy-terminated methylhydrogenpolysiloxane at a viscosity of 20 cP and 0.2 parts of 3-methyl-1-butyn-3-ol1-reaction inhibitor-Torla were dissolved in 150 parts of toluene. A pressure sensitive adhesive composition (40% non-volatile) was obtained by adding chloroplatin-diacid-vinyl-1-oxane to this mixture in an amount sufficient to guarantee 100 ppm platinum based on the combined amount of the previous poly-1-oxanes.

9,84276 This composition was applied to a 50 micron thick aluminum sheet and heated at 80 ° C for 5 minutes to obtain a 50 micron thick film after heating. The film-forming performance, adhesion force, sphericity and cohesive force of the obtained aluminum 1 condition-sensitive, compression-sensitive strip were measured, and these results are given in Table 1.

For comparison, a pressure-sensitive adhesive composition (40% non-volatile) was produced as above, except that dimethyl oxy-1-dimethyl dust was dissolved in oxa having a viscosity of 60,000 cP from dimethyl vinyl to oxy-1op wood dimethyl polyoxane. This composition was evaluated by the same methods as above, and these results are also given in Table 1.

According to Table 1, the pressure-sensitive adhesive composition of the present invention provides excellent adhesion, ball shape, and cohesive force, all of which are important properties for a pressure-sensitive adhesive. On the other hand, a pressure-sensitive 111 composition using 60,000 cP of dimethylvinyl-sinoxy-terminated dimethyl-dusted 1-oxane gave poor values for adhesion, ball mass and cohesive force.

table 1

Measurement Example 1 Compare 1u

Adhesion force, g / 2.5 cm 3800 2000

Bullying 29 17

Cohesion force, mm 0 2.0

Example 2

Exactly 55 parts of methyl 1 was dusted with 1 oxane a containing Me S i 0 3 1/2 and S10 4 units in a molar ratio of 0.7: 1, 45 parts of the dimethyl-silyloxy-terminated dimethylsiloxane-co-methyl-phenyl-s11 oxane copolymer rubber a with vinyl group content 0.02% and phenyl group content 3.0%, 0.4 part of trimethylsiloxy-terminated dimethylsoxane-co-methylhydrogen 1 oxa-8 84276 n-copolymer having a viscosity of 6 cP (s 11 of methyldehyde hydrogen atoms and methyl molar ratio of 1: 3), and 0.2 parts of phenylbutynol addition reaction inhibitor was dissolved in 150 parts of toluene. A pressure sensitive adhesive composition with 40% non-volatility was obtained by adding your chloroplatinic acid vinyl 1 to the oxane clump in this mixture in an amount sufficient to give 180 ppm platinum based on the combined amount of dusted oxanes. This composition was evaluated as described in Example 1 and the results were: adhesion force = 3800 g / 2.5 cm, sphericity = 29, cohesion force = 0.3 mm.

According to these data, this pressure-sensitive adhesive composition performed very well as a pressure-sensitive silicon line at a relatively low rl s 11 coupling temperature up to 80 ° C.

Example 3

Exactly 57 parts of methyl were dusted with 1 oxane containing Me SiO

3 1/2 and SiO 2 units in a molar ratio of 0.7: 1.43 parts of dimethyl-vinyl-1-oxy-terminal dimethyl-11-oxane-co-methyl vinylsiloxane copolymer rubber with a vinyl group density of 0.05%, 0, 2 parts of trimethyl-11-oxy-terminated methylhydrogen polysiloxane having a viscosity of 20 cP and 0.2 parts of 3-methyl-3-penten-1-yn-1 reaction inhibitor were dissolved in 150 parts of toluene. A pressure-sensitive film composition (40% non-volatile) was obtained by adding chloropiatinic acid-vinyl-1-oxane-coke to this mixture in an amount sufficient to give 110 ppm of platinum based on the 1-oxane portion of the dust. This composition was evaluated as described in Example 1, and the results were: adhesion force = 3700 g / 2.5 cm, ball shape = 25, cohesion force = 0.1 mm.

Example 4

Exactly 57 parts of methyl 1 dusted oxane containing Me: SO 2 and SiO 2 units in a molar ratio of 0.7: 1, 43 parts of dimethyl vinyl-terminated dimethyl-dusted 1 oxane with vinyl group content of 0 .07% and a volume of 600,000 cP, 0.4 part of the methylmethyl-oxy-1-dlmethyl-oxane-co-methyl-hydrogen-siloxane copolymer having a viscosity of 6 cP (in the presence of a molar ratio of hydrogen atoms and methyl groups of 1: 1). .2 parts of the phenylbutynol adduct reaction inhibitor were dissolved in 25 parts of toluene. A pressure sensitive adhesive composition (80% non-volatile) was obtained by adding the chloro-platinum acid-vinyl-siloxane complex to this mixture in an amount sufficient to give 110 ppm platinum based on the polysiloxane slurry. This composition was evaluated as described in Example 1, and the results were: adhesion volume * 4200 g / 2.5 cm, ball adhesive = 2, cohesive force = 0.3 mm.

Comparative Example 1

Exactly 150 parts of toluene were added to 55 parts of methyl dust with oxane containing Me S10 and S10 units in a molar ratio of 0.7: 1.0 and 45 parts of hydroxyl-terminated polydimethylsilane. rubber. This was heated at 110 ° C for 6 hours, and 1 part of benzoylperoxide, diluted with a small amount of xylene, was added with vigorous stirring to obtain a pressure-sensitive s11 icon 111 composition. This was applied, heated and evaluated as described in Example 1, and the results were: film thickness = 48 microns, adhesion volume = 4000 g / 2.5 cm, ball shape = 30; cohesive slovol could not be measured because the strip slipped off the stainless steel plate.

Since the pressure-sensitive silicone adhesive composition of the present invention is an addition-reactive pressure-sensitive icon adhesive composition in which components (B) to (E) are mixed with polydiorganosine oxane having alkenyl groups at both ends of the molecule and having a viscosity of at least 500,000 cP, it can be temperatures and it becomes a pressure-sensitive adhesive with excellent adhesiveness and adhesion.

Claims (7)

1. Pressure sensitive silicone adhesive composition containing: (A) between 30 and 70 parts by weight of polydiorganosiloxane of the general formula (I): R'R2Si0 (R2SiO) nSiR2R 'I wherein R represents an univalent hydrocarbon group, R' represents an alkenyl group and the number of repeat units integers, (B) between 70 and 30 parts by weight of an organopolysiloxane, consisting of R 3 3 SiO 2 y 2 units and SiO 2 units, the ratio of the former to the latter being between 0.6: 1 and 0.9: 1, where R 'represents a group selected from alkyl groups, alkenyl groups and hydroxyl groups, wherein at least 95% of all R' groups are methyl groups, (C) an amount of organohydrogen polysiloxane having an average etmine tone 2 silicone bonds per hydrogen atom in each molecule, said amount being sufficient to yield between 1 and 20 silicone bonded hydrogen atoms per alkenyl group in component (A), (D) a platinum containing catalyst for an addition reaction between the silicone bonded a the lkenyl groups and the silicone bonded hydrogen atoms in an amount sufficient to yield between 0.1 and 1000 parts by weight of platinum per each part of the composite amount of components (A) - (C) based on the weight, and (E) between 25 and 400 parts by weight of an organic solvent for components (A) - (C), characterized in that the number of repeating units of formula (I) is large enough to give the polydiorganosiloxane in part (A) a viscosity of at least 500,000 cP at a temperature of 25 ° C . Composition according to Claim 1, characterized in that the formula of the polydiorganosiloxane is: ViMe2SiO (Me2SiO) nSiMe2Vi where Me represents a methyl group and We denotes a vinyl group. is 84276 Composition according to claim 2, characterized in that the formula of the organohydrogen polysiloxane is: Me3S10 (MeHS10) a (Me2S10) bS1Me3 where the average value of a is at least 3 and the average value of b is 0 or more. Composition according to claim 1, characterized in that the polydiorganosiloxane has the formula: ViMe2S10 (Me2S10) n_c (MePhSiO) cSiMe2Vi where Me represents a methyl group, VI represents a vinyl group, Ph represents a phenyl group and c has a value of 1-n. Composition according to claim 4, characterized in that the organohydrogen polysiloxane has the formula: N Me3 SiO (MeHSiO) a (Me2 SiO) bSiMe3 where the average value of a is ethylene 3 and the average of b is 0 or more. Composition according to claim 1, characterized in that the polydiorganosiloxane has the formula: VlMe2SiO (Me2SiO) n_d (MeViSiO) dSiMe2Vi where Me represents a methyl group, We denotes a vinyl group and d has a value of 1-0, In. Composition according to claim 6, characterized in that the organohydrogen polysiloxane has the formula: Me3SiO (MeHSiO) a (Me2SiO) bSiMe3 where the average value of a is ethylene 3 and the average value of b is 0 or more.